Motor fuel composition



United States Patent Int. Cl. C101 N22 US. CI. 44-66 6 Claims ABSTRACT OF THE DISCLOSURE Anti-icing, anti-stalling and corrosion inhibited motor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range and a minor amount of an amine salt of a trimer of an unsaturated acid having 18 carbon atoms.

This invention relates to a motor fuel composition for internal combustion engines having outstanding anti-icing, anti-stalling properties and a high level of corrosion inhibiting properties. The improvements in the motor fuel are based on the discovery of the effect of certain amine salts of trimer acid.

It is well known that spark-ignited internal combustion engines employing highly volatile winter-grade motor fuels are prone to stalling during engine start-up periods. This problem is generally experienced under atmospheric conditions of high humidity and relatively low temperatures, i.e., humidities above about 70%, and temperatures in the range of about 30 to 60 F. Engine stalling under these conditions is attributed to the blocking of the air passage that exists between the carburetor throat and throttle blade during engine idling by the deposition of ice on the internal metal parts of the carburetor. The ice is formed from the water vapor present in the air drawn into the carburetor. This water vapor is condensed and solidified due to the refrigerating effect produced by the vaporization of the motor fuel in the carburetor.

The stalling problem noted above is encountered with the use of a winter-grade motor fuel containing a high proportion of volatile hydrocarbons in the gasoline boiling range. Volatility of these fuels is expressed as the Reid vapor pressure. Fuels having a Reid vapor pressure above about 9 and up to about 13.5 are particularly prone to engine stalling due to ice formation under too humid atmospheric conditions.

Rust and corrosion inhibiting properties are also important in a modern gasoline. Commercial gasoline generally is constantly in contact with ferrous metal surfaces from the time it is produced at the refinery, during transport by ship or pipeline and during storage both at the service station and in the customers fuel tank. Since a small amount of water is inevitably present dissolved in the gasoline in a concentration sufiicient to promote rusting, the use of an effective corrosion inhibitor in the fuel is essential.

It is desirable to provide the properties required by the gasoline with the smallest quantities of additives possible. It is still more desirable to provide the required properties with the least number of additives. Both of these steps lead to simplified handling procedures and to substantial economies in treating the fuel composition. Of equal importance, the reduced amounts and types of additive in the fuel minimize or eliminate the development of undesirable side effects, such as formation of ice haze, precipitates or foams in the fuel, carburetor fouling and the like.

A novel motor fuel composition has now been discovered characterized by having outstanding anti-icing, anti-stalling properties and good rust inhibiting properties thereby meeting the foregoing objectives.

In accordance with this invention, there is provided amotor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range containing from about 0.0003 to about 0.0015 weight percent of the salt reaction product of an amine and trimer acid represented by a formula from the group consisting of:

in which R is a tertiary alkyl radical having from 4 to 18 carbon atoms, x is an integer from 1 to 3 and X is the trimer of :a C unsaturated acid, or a salt in which R is a normal or-a secondary alkyl radical having from 4 to 18 carbon atoms, x is 2 and X is the trimer. of a C unsaturated acid, and a salt having the formula in which R is a normal alkyl radical having from 4 to 18 carbon atoms and X is the trimer of a C unsaturated acid.

There appears to be criticality in the particular group of noted amine-trimer acid salts which are effective as anti-icing, anti-stalling additives and as rust inhibitors in gasoline. A number of closely related compounds do not meet the minimum standards for effectiveness when tested.

Another unusual feature of this invention is the surprisingly low concentration of the selected amine salts of trimer acid which are effective for the noted purposes. Thus, it was surprising to discover that a concentration of the amine salt of the invention in the range from 0.0003 and 0.0015 weight percent is highly effective for imparting the desired properties to a motor fuel composition. The preferred concentration of the amine salt of trimer acid of this invention is an amount ranging from 0.0004 to 0.00075 weight percent which amounts correspond to about 1 and 2 (p.t.b.) pounds per thousand barrels respectively.

The anti-icing, anti-stalling and corrosion inhibiting additive of this invention is represented by a formula from the group consisting of in which R is a tertiary alkyl radical having from 4 to 18 carbon atoms, x is an integer from 1 to .3 and X is the trimer of a C unsaturated acid, or in which R is a normal or a secondary alkyl radical having from 4 to 18 carbon atoms, x is 2 and X is the trimer of a C unsaturated acid, and a salt having the formula in which R is a normal alkyl radical having from 4 to 18 i:arbon atoms and X is the trimer of a C unsaturated aci Examples of the tertiary alkyl amines which can be used for preparing the noted salts are tertiary octyl primary amine, tertiary dodecyl primary amine, tertiary butyl primary amine and tertiary hexadecyl primary amine. Examples of suitable normal alkyl primary amines are n-octyl primary amine, n-decyl primary amine, n-dodecyl primary amine, n-hexadecyl primary amine and the like. Examples of suitable secondary alkyl primary amines are secondary C1044 alkyl primary amine and secondary C1445 alkyl primary amine.

Trimer of unsaturated acids for this invention are prepared according to known methods. In particular, dienoic and trienoic acids containing 18 carbon atoms having conjugated olefinic linkages are polymerized or condensed according to the method disclosed in US. 2,632,- 695. Specific olefinic acids which can be employed to prepare the trimer acids include linoleic, linolenic, 9,11-octadecadienoic, and eleostearic acids. The trimer acids have three free carboxylic acid groups each of which will react with anamine compound to form a salt. Because of the three acid groups, trimer acids will form monosalts, disalts and trisalts with amines. As noted above, there appears to be criticality in the particular salts which are effective in this invention. In general, the disalts are effective while, with the exception of tertiary alkyl primary amine trisalt of trimer acid, the trisalts were not effective.

The amine salts or trimer acids are prepared by mixing one, two or three molar portions of the amine with one molar portion of the trimer acid. The reaction is spontaneous but it can be speeded to completion by the application of moderate heat. Amide formation is to be avoided. Alternatively, the amine and the trimer acid can be dissolved in gasoline and salt formation permitted to take place in situ.

The action of the amine salts of trimer acids as antistalling, anti-icing additives was evaluated in a glass tube carburetor icing bench test consisting of a glass tube containing a simulated throttle plate so that cooled moisturesaturated air from an ice tower is drawn through the simple glass tube gasoline carburetor by suction from a vacuum pump. The gasoline sample is placed in a sample bottle and is drawn into the glass carburetor through a hypodermic needle which is usually 20 gauge. Evaporation of the gasoline in the glass tube further cools the cold moist air with resulting ice formation on the simulated throttle plate. The formation of ice on the throttle plate causes a pressure differential which is registered on a manometer. The fuels are rated in terms of seconds required to attain a pressure differential of 0.5 inch of mercury. Since most fuels stall in an engine in 1 to 4 minutes, 300 seconds is the maximum time for a run. A recording of 300 seconds denotes no simulated stall (pressure differential did not reach 0.5 inch of mercury), within the test period. Each fuel is run three times in succession and the average is reported. If the differences in runs are great the glass tube carburetor and test throttle are washed with alcohol and the runs repeated. A leaded winter-grade premium gasoline having a Reid vapor pressure of about 13 gives a stall in about 45 to 55 seconds in this test. Additives which raise the stalling time to over 200 seconds are effective anti-stalling, anti-icing additives.

The rust inhibiting properties of the gasoline of the invention were determined in a modified ASTM rust test. In this test, a cold-rolled polished steel strip is put into 90 cc. of the fuel sample in a tall-form 4 oz. bottle. This bottle is shaken for 15 seconds and then cc. of distilled water are added to the bottle and the bottle again shaken for 15 seconds as before. The test sample is then maintained at room temperature for 24 hours. After this period of time, the steel strip is removed and visually examined for the amount of rust on the metal surfaces. The rust is reported as percent rust on the parts of the metal surfaces that were immersed in the fuel layer.

The base fuel employed to evaluate the effectiveness of the amine-trimer acid salts as anti-icing, anti-stalling and corrosion inhibitors for gasoline was a winter grade premium gasoline having an octane rating of about 100.0 and containing 3 cc. of TEL per gallon. This winter grade gasoline, which had a 50% ASTM distillation point of 230 F. and a Reid vapor pressure of about 11 lbs. was ideally suited for testing the stalling characteristics of the additives because of its high vapor pressure. The base fuel had an average stalling time of 44 seconds in the above described test.

The following table gives the anti-icing, anti-stalling and rust inhibiting properties of amine salts of trimer acid of the invention as Well as the results obtained using similar materials.

TABLE Concentratlon,lbs./1,000 stalling bbl.

time, sec.

Rust, percent Additive acid.

7 n-Octyl tertiary amine 2 Inonosalt oi the trimer of linoleic acid.

8 n-Octyl tertiary amine 1 di-salt oi the trimer of linoleic acid' 9 n-Octyl tertiary amine 2 tri-salt of the trimer of linoleic acid.

11 Secondary 010-14 alkyl primary amine disalt of the trimer of linoleic acid.

12 Secondary C1044 alkyl 2 primary amine trisalt of the trimer of linoleic acid.

It is evident from the foregoing tests that the additives of Runs 2, 3, 4, 5, 7, 8, and 11 have outstanding anti-icing, anti-stalling properties at remarkably low concentrations. Closely related salts employed in Runs 6, 9, 10 and 12 were ineifective as anti-stalling additives. The rust test in Runs 2, 3, 4, 5, 7, 8, and 11 show that these additives substantially reduced or practically eliminated the rusting problem that is normally experienced with nonadditive fuels and even with some fuels containing amine salts of trimer acid.

Obviously, many modifications and variations of the invention, as hereinafter set forth, may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A motor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range and from about 0.0003 to 0.0015 weight percent of the salt reaction prodact of an amine and trimer acid represented by a formula from the group consisting of in which R is a tertiary alkyl radical having from 4 to 18 carbon atoms, x is an integer from 1 to 3 and X is the trimer of a C unsaturated acid,

or such a product having the aforesaid formula in which R is a normal or a secondary alkyl radical having from 4 to 18 carbon atoms, x is 2 and X has the value noted above. and a salt having the formula 's in which R is a normal alkyl radical having from 4 to 18 carbon atoms and X has the value noted above. 2. A motor fuel composition according to claim 1 in which said salt reaction product is the tertiary-octyl primary amine tri-salt of the trimer of linoleic acid.

3. A motor fuel composition according to claim 1 in which said salt reaction product is the tertiary octyl primary amine di-salt of the trimer of linoleic acid.

3. A motor fuel composition according to claim 1 in which said salt reaction product is the tertiary octyl primary amine di-salt of the trimer of linoleic acid.

4. A motor fuel composition according to claim 1 in which said salt reaction product is the n-octyl tertiary amine di-salt of the trimer of linoleic acid.

5. A motor fuel composition according to claim 1 in which said salt reaction product is the secondary C1044 alkyl primary amine di-salt of the trimer of linoleic acid.

6. A motor fuel composition according to claim 1 containing from about 0.0004 to 0.00075 weight percent of 10 said salt reaction product.

2,330,524 9/1943 Shields 252-392 6 2,736,658 2/1956 Pfohl et 'al 44-66 XR 2,758,086 8/1956 Stuart et a1. 4466 XR 2,798,045 7/1957 Buck et a1 44-66 XR 2,939,842 6/1960 Thompson 4471 XR 2,976,179 3/1961 Westlund et a1. 44-66 XR OTHER REFERENCES Kalichevsky et a1.: Petroleum Refining with Chemicals, Elsevier Publishing Co., N.Y., 195 6, p. 480.

DANIEL E. WYMAN, Primary Examiner.

W. J. SHINE, Assistant Examiner.

US. Cl. X.R. 

